Strangely glowing dark clouds float
serenely in this remarkable and beautiful image
taken with the Hubble Space Telescope. These dense,
opaque dust clouds -- known as "globules"
-- are silhouetted against the red glow of hydrogen
gas and bright stars in the busy star-forming region,
IC 2944. Astronomer A.D. Thackeray first spied the
globules in IC 2944 in 1950. Globules like these
have been known since Dutch-American astronomer
Bart Bok first drew attention to such objects in
1947. Astronomers still know very little about their
origin and nature, except that they are generally
associated with areas of star formation. IC 2944
is filled with gas and dust that is illuminated
and heated by a loose cluster of massive stars.
These stars are much hotter and more massive than
our Sun.

The largest of the globules in this image
is actually two separate clouds that gently
overlap along our line of sight. Each cloud
is nearly 1.4 light-years along its longest
dimension. Collectively, the clouds contain
enough material to make more than 15 stars
like our Sun.

2. What does Hubble's view
reveal to astronomers?

Thanks to the remarkable resolution offered
by the Hubble telescope, astronomers can,
for the first time, study the intricate
structure of these globules. The globules
appear to be fragmented, as if in the process
of being torn apart. When radio astronomers
observed the faint hiss from molecules within
the globules, they realized that the globules
are actually in constant, churning motion,
moving supersonically among each other.
This chaotic motion may be caused by the
powerful ultraviolet radiation from the
luminous, massive stars. These stars also
heat the glowing hydrogen gas, causing it
to expand against the globules, leading
to their eventual destruction. Despite their
serene appearance, the globules may actually
be likened to clumps of butter on a red-hot
pan.